EP0276112A1 - Bilderzeugungseinrichtung - Google Patents

Bilderzeugungseinrichtung Download PDF

Info

Publication number
EP0276112A1
EP0276112A1 EP88300378A EP88300378A EP0276112A1 EP 0276112 A1 EP0276112 A1 EP 0276112A1 EP 88300378 A EP88300378 A EP 88300378A EP 88300378 A EP88300378 A EP 88300378A EP 0276112 A1 EP0276112 A1 EP 0276112A1
Authority
EP
European Patent Office
Prior art keywords
image forming
image
detecting
accordance
humidity
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP88300378A
Other languages
English (en)
French (fr)
Other versions
EP0276112B1 (de
Inventor
Tadashi Ishikawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP62009562A external-priority patent/JP2808108B2/ja
Priority claimed from JP62009561A external-priority patent/JP2808107B2/ja
Priority claimed from JP62009563A external-priority patent/JP2604144B2/ja
Application filed by Canon Inc filed Critical Canon Inc
Publication of EP0276112A1 publication Critical patent/EP0276112A1/de
Application granted granted Critical
Publication of EP0276112B1 publication Critical patent/EP0276112B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/23—Reproducing arrangements
    • H04N1/29—Reproducing arrangements involving production of an electrostatic intermediate picture
    • H04N1/295—Circuits or arrangements for the control thereof, e.g. using a programmed control device, according to a measured quantity
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/01—Apparatus for electrographic processes using a charge pattern for producing multicoloured copies
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/50—Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control
    • G03G15/5033—Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control by measuring the photoconductor characteristics, e.g. temperature, or the characteristics of an image on the photoconductor
    • G03G15/5037—Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control by measuring the photoconductor characteristics, e.g. temperature, or the characteristics of an image on the photoconductor the characteristics being an electrical parameter, e.g. voltage
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/00025—Machine control, e.g. regulating different parts of the machine
    • G03G2215/00029—Image density detection
    • G03G2215/00033—Image density detection on recording member
    • G03G2215/00054—Electrostatic image detection

Definitions

  • the present invention relates to an image forming apparatus wherein an ambient condition or conditions are measured, in response to which an image forming condition or conditions are controlled.
  • an electrophotographic image forming apparatus that in order to maintain a constant density of the formed image, a potential of a charged photosensitive drum, a developing bias potential applied to a developing device or the like is adjusted so as to control the image forming conditions influential to a contrast potential of an image or a foggy background preventing potential or the like.
  • an image forming condition is determined in response to the properties of the respective color developers so as to provide substantially the same image density for all colors, as disclosed in U.S. Serial No. 330,551.
  • U.S. Serial No. 087,918 and Japanese Patent Application 86465/1980 propose in the field of ink jet printers that temperature or humidity is detected, in response to which the image signal is controlled for each colors in a reference value of an A/D conversion, a gain of an amplifier, a coefficient of color correction or the like.
  • the control of the image signal requires a high speed processing of the signal, which results in an expensive circuit.
  • the method of maintaining a constant surface potential of the photosensitive member is changed in accordance with a humidity, as disclosed in U.S. Patent No. 4,573,788.
  • the surface potential is stabilized using a predetermined operational expression within a predetermined humidity range, but in the other range, the operational expression is not used, and measurement of the actual surface potential of the photosensitive member and adjustment of the charger and exposure amount are repeated so that the potential approaches the target potential, and therefore, the time required for reaching the target potential is very long as the case (humidity) may be.
  • the image forming apparatus comprising a rotary type developing device 1 having a rotor carrying an yellow developing device 1Y, a magenta developing device 1M, a cyan developing device 1C and a black developing device 1BK.
  • the apparatus further includes a developer (toner) supplying device for supplying the developer to the developing device 1.
  • the supplying device 2 includes a yellow hopper 2Y, a magenta hopper 2M, a cyan hopper 2C and a black hopper 2BK.
  • a photosensitive drum 3 is rotatable in the direction indicated by an arrow, and a surface thereof is uniformly charged by a charger 4.
  • An unshown original is exposed to light, and an yellow image signal is obtained by a proper photo-electric conversion.
  • a laser beam E is modulated in accordance with the yellow image signal and is projected onto the surface of the charged photosensitive drum 3, so that an electrostatic latent image is formed on the photosensitive drum 3.
  • the yellow developing device 1Y situated beforehand to its developing position develops the electrostatic latent image. Which one of the developing devices 1Y, 1M, 1C and 1BK is placed at the developing position is discriminated by unshown microswitches.
  • a transfer sheet for receiving an image is transported through a sheet guide 5a, a sheet feeding roller 6 and a sheet guide 5b and is held by a gripper 7.
  • the sheet is electrostatically wrapped around a transfer drum 9 by a contact roller 8 and an opposite electrode.
  • the transfer drum 9 is rotated in the direction indicated by an arrow in synchronism with the photosensitive drum 3.
  • the image developed and visualized by the yellow developing device 1Y is transferred to the transfer sheet at the transfer station provided with a transfer charger 10.
  • the transfer drum 9 continues to rotate while holding the transfer sheet to be prepared for the image transfer in the next color, more particularly, a magenta image in the example of Figure 1 embodiment.
  • the photosensitive drum 3 is discharged by a discharger 11 and is then cleaned by a cleaning member 12.
  • the photosensitive drum 3 is again charged by a charger 4 and is exposed to the laser beam which is then modulated in accordance with a magenta image signal.
  • the rotary developing device 1 rotates to place the magenta developing device 1M at a predetermined developing position to perform a developing operation in the magenta color.
  • the above-described steps are repeated for each of the cyan and black colors.
  • the visualized four color image on the transfer sheet is discharged by dischargers 13 and 14.
  • the transfer sheet is released from the gripper 7 and is separated from the transfer drum 9 by a separation pawl 15 and is transported to an image fixing device 17 by a conveying belt 16.
  • a series of full color printing operations is completed to provide a full-­color print image.
  • an ambience sensor 19 including a humidity sensor and a temperature sensor disposed at a position where the moisture absorption of the toner is properly reflected, such as a neighborhood of a toner hopper or the neighborhood of the developing device.
  • FIG 2 is a block diagram of the control system for Figure 1 apparatus.
  • the primary charger 4 is supplied with a high voltage from a high voltage source 4a.
  • the primary charger 4 is provided with a grid for controlling an amount of charge applied to the photosensitive drum 3, the grid being supplied with electric power from a grid bias source 4b.
  • a developing bias source provides a developing bias in the form of a combined AC and DC voltages.
  • the outputs of the power sources are controlled by a microcomputer 18 or the like.
  • the control means 18 is also connected to the ambience sensor 19 and a potential sensor 20.
  • V D is a surface potential of the area not exposed to the light beam
  • V L is a surface potential of the area exposed to the light beam.
  • the surface potential V D that is, the amount of charge is proportional to the grid bias V G .
  • the surface potential V L after the light exposure has a similar tendency.
  • a ratio of change of V D with respect to a change of the grid bias V G is larger than that for V L , that is, ⁇ > ⁇ .
  • the control means 18, before execution of the printing sequenses measures the potentials V D and V L using a potential sensor 20 for predetermined grid voltages V G1 and V G2 , so that charging curves for the potentials V D and V L with respect to a grid voltage as shown in Figure 3 is assumed on the basis of data by the potential sensor 20.
  • a grid voltage which provides a predetermined image contrast that is, a difference between a DC component of a developing bias which will be described hereinafter and a surface potential V L after image exposure, or V D -V L is determined on the basis of the charging curve.
  • the grid voltage is determined in this manner, and the grid bias source 4b is controlled to provide the voltage.
  • a developing bias D B is determined to be lower than the potential V D by a predetermined voltage (V B ) so as to prevent deposition of the toner onto the area corresponding to the background of the image, that is, the area corresponding to V D in this case since a reversal development is effected, and the developing bias source 1 ⁇ is controlled, accordingly.
  • Figure 4 is a graph showing influence of humidity to the image density when the printing is effected under the same image forming conditions.
  • the density decreases with the humidity under the same image forming conditions, and it increases with the increase of the humidity. Therefore, the humidity is detected, and a contrast potential Vcont corresponding to a humidity is determined.
  • the image forming condition or conditions are set, whereby a stabilized image can be obtained irrespective of variation of the ambient conditions.
  • the image density is different if the color of the developer is different even in the same humidity. Therefore, the image forming condition or conditions are made variable for the respective colors, whereby the image density variation depending on the color of the developer can be corrected.
  • FIGS. 5A, 5B and 5C are flow charts, operations of the control means 18 in this embodiment will be described.
  • the processing shown in those flow charts is programmed in a ROM 23.
  • the ambience sensor 19 measures the temperature and the relative humidity every 30 minutes, for example, or several times in every 30 minutes, and an average value is determined.
  • the ambience sensor 19 is operative irrespective of the state of a main switch supplying power to the image forming apparatus, by an interruption function using a timer 21.
  • the data are stored in a buffer area in a memory 22 capable of storing data for 8 hours, for example.
  • an absolute humidity or a value corresponding thereto is determined on the basis of the stored data. This is done because the image density is proportional to the absolute humidity, that is, an amount of water in the air.
  • the humidity sensor in this embodiment is a relative humidity sensor having a strong temperature dependence.
  • e s saturated vapour pressure
  • p pressure
  • the ROM stores a table for every 1 °C, and a table search is performed for the determination.
  • a discrimination is made as to whether or not the absolute humidity (mixture ratio) calculations have been executed for the eight hour period, and if so, at step 3, average values x, y and z are determined for the latest 2 hours, 4 hours and 8 hours, respectively.
  • the averages x, y and z are parameters when the contrast is determined.
  • the humidity change is discriminated.
  • the discrimination is made as to whether or not the two hours average x of the mixture ratio is 16.5 g or larger, and if so a flag is set to CONT1. In this case, it is discriminated that the high humidity condition continues for not less than two hours.
  • the discrimination is made as to whether or not the current mixture ratio w is 16.5 g or larger, and if so, the flag is set to CONT2.
  • the current mixture ratio w is represented by the latest humidity data.
  • the flag CONT2 corresponds to the discrimination that the low humidity condition continued for the past two hours, but the humidity is increasing now.
  • the discrimination is made as to whether or not the eight hours average z is 9 g or larger, and if so, the flag is set to CONT3. This means that the humidity has been middle (middle between the high humidity and the low humidity) for 8 hours or longer.
  • step 7 the discrimination is made as to whether or not the four hours average y is 9 g or larger, and if so, the flag is set to CONT4. It is now discriminated that the humidity is changing from the low humidity condition to an intermediate or middle humidity condition. If not, that is, the four hours average is less than 9 g, the low humidity condition is discriminated so that the flag is set to CONT5.
  • the above described method of discrimination is performed because the speeds of the moisture absorption and dehumidification of the toner are different between when the humidity is changing from the low humidity condition to the high humidity condition and when it is changing from the high humidity condition to the low humidity condition.
  • the speed of the dehumidification when the humidity is changing from the high humidity condition to the low humidity condition is lower than the speed of the moisture absorption when the humidity is changing from the low humidity condition to the high humidity condition.
  • a variable H for the contrast calculation is determined on the basis of the contrast flag.
  • the CONT1 when the CONT1 is selected, it means that the toner is completely influenced by the high humidity condition, and therefore, the variable H corresponds to the two hours average x.
  • the CONT2 when the CONT2 is selected, that is, it is between the low humidity condition and the high humidity condition, the variable H is an average of the two hours average x and the current value w, that is, (x+w)/2.
  • the contrast potential Vcont is calculated, and at step 9, it is stored in the memory. This is repeated for four colors.
  • one of CONT1 - ­CONT5 is selected on the basis of the average humidity data x, y and z and the current value w. If the flag of CONT3 is selected, a type of the variable H and the coefficient a3 and b3 are obtained from the table stored in the memory ROM23, thus determining the calculation equation. Using the equation, the contrast potential Vcont is determined using the actual values for the variation H.
  • Figure 6 is a plot of contrast potentials with respect to humidities for respective colors of the developer. As will be understood from this Figure, the coefficients are changed for the respective colors, the difference in the density variation depending on the colors can be accommodated and can be properly corrected.
  • the photosensitive drum is rotated, and the primary high voltage source 4a is energized.
  • the grid bias is set to a predetermined level V G1 , and a surface potential of the photosensitive drum in the dark area V D1 is measured and stored in the memory.
  • the laser is actuated, and the drum is exposed to the maximum amount of the laser beam.
  • the grid bias is set to another predetermined level V G2 , and the surface potential V L2 is measured, and then, the laser is deactivated.
  • the surface potential V D2 is measured, and the data is stored in the memory 22.
  • V D and V L measurements with the laser actuation and deactivation and the order of setting V G1 and V G2 may be changed for the convenience of the sequential operation.
  • the processings A and B are independent from each other, and either will go first, and it is not necessary that the processings are performed simultaneously.
  • the processing C has to be performed after the processings A and B are performed.
  • the above described fog preventing voltage V B and the contrast voltage Vcont obtained by the processing A are read out of the buffer area.
  • V D ⁇ (V G -V G1 ) + V D1
  • DB V D - V B
  • step 26 if it is discriminated that the above processing is completed for four colors, the processing terminates.
  • the grid bias control value V G and the developing bias control value DB have been obtained. Then, the image forming operation is performed using the grid bias voltage V G and the developing bias DB obtained in the manner described above. Since those values are determined not only on the basis of the humidity condition under which the developer has been placed but also on the basis of the property difference among the developers having different colors, an extremely stabilized proper density image can be obtained.
  • the present invention takes as an important factor for determining the image forming condition or conditions the history of the humidity. Therefore, it is required that the apparatus is always energized to allow the temperature data and the relative humidity data to be taken.
  • the buffer area does not contain any data or it contains false data. Therefore, the proper image forming conditions would not be provided immediately after the repairing or the like.
  • FIG 7 an embodiment of the present invention to obviate this inconvenience will be described.
  • the apparatus of Figure 7 is provided in addition to Figure 1 apparatus with a rewriting means 24 for rewriting the humidity data stored in the memory 22. In this apparatus, following process is executed.
  • the temperature and humidity are measured immediately after the apparatus is energized.
  • the data are stored in the entirety of the 8 hours buffer area of the memory, assuming that the measured temperature and humidity are constantly continued for 8 hours.
  • the above-described processings A, B and C are executed.
  • an expert service man or the like takes a copy using a normal copying sequence to take a sample of an image.
  • the image density is checked. The image density is not always proper. For example, if the humidity is high at the time of insulation of the apparatus, the eight hours humidity data are all high humidity data, and therefore, the contrast potential is determined on the data.
  • the toner supplied into the apparatus at the time of installation is mainly influenced by the moisture under the ambience sealed in the plant, which might be completely different from the ambience of the installation.
  • the humidity data is rewritten by a humidity data rewriting means 24 using a servicing mode. In this mode, the humidity data are rewritten all at once.
  • the humidity data rewriting means 24 includes two keys, one of which can rewrite toward the low humidity side, and the other of which rewrites toward the high humidity side. By depressing the switch, the humidity data is changed by an amount corresponding to one contrast change.
  • the one contrast change corresponds to 50 V of the drum surface potential.
  • the proper image can be provided from the start. Furthermore, with elapse of the time, the temperature and humidity data are accumulated so that the proper images can be provided.
  • the property of the developer can be extremely different from lot to lot.
  • the coefficient of the contrast calculation is fixed, a proper image density can not be obtained as the case may be.
  • FIG 8 there is shown an embodiment which can provide a proper image even if that case.
  • the apparatus of this embodiment is provided in addition to Figure 1 apparatus with memory means 22 ⁇ which can keep the memory even if the power supply is stopped.
  • the memory means 22 ⁇ includes a RAM and a back-up battery or includes EPROM.
  • the memory means 22 ⁇ stores the data to be added at the time of the contrast calculation for each of the colors. The contents thereof can be rewritten by a changing means 25 in a servicing mode, so that proper adjustment can be effected, checking the image samples.
  • the contrast is changed, and the contrast is stored in the memory at step 10. Further, the humidity-contrast curve of Figure 6 becomes as shown in Figure 9.
  • the solid line curve is a curve at the time of initial setting, and when, for example, the image density is lower than the initial setting, Voff is positive, and the broken line curve is used. If the density is high, V ⁇ off becomes negative as shown in chain lines.
  • a RAM 22 ⁇ may store coefficients a n and b n and variable H n , and the coefficients a n and b n may be rewritten by the changing means 25 for each of the CONT1 - CONT5 and for each color. By this, further proper contrast value can be provided.
  • the present invention is applicable to usual monochromatic image forming apparatus. Also, the present invention is applicable to the apparatus wherein an image of an original is directly projected on the photosensitive member, and the image thereof is formed.
  • the ambient detecting means detects the absolute humidity.
  • the image density may be controlled on the basis of the measurement of a factor or factors influential to the developer such as temperature other than the humidity to control the image density.
  • the image forming condition is determined on the basis of the charge potential on the photosensitive drum, the potential after the light application and the potential of the developing bias.
  • other condition or conditions may be controlled such as charged potential of the developer or amount of light application or the like.
  • the contrast levels are divided into five levels (CONT1 - ­CONT5). However, the number of division may be increased further.
EP88300378A 1987-01-19 1988-01-18 Bilderzeugungseinrichtung Expired - Lifetime EP0276112B1 (de)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP62009562A JP2808108B2 (ja) 1987-01-19 1987-01-19 画像形成装置
JP9561/87 1987-01-19
JP62009561A JP2808107B2 (ja) 1987-01-19 1987-01-19 画像形成装置
JP9562/87 1987-01-19
JP9563/87 1987-01-19
JP62009563A JP2604144B2 (ja) 1987-01-19 1987-01-19 画像形成装置

Publications (2)

Publication Number Publication Date
EP0276112A1 true EP0276112A1 (de) 1988-07-27
EP0276112B1 EP0276112B1 (de) 1993-03-31

Family

ID=27278545

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88300378A Expired - Lifetime EP0276112B1 (de) 1987-01-19 1988-01-18 Bilderzeugungseinrichtung

Country Status (3)

Country Link
US (1) US4888618A (de)
EP (1) EP0276112B1 (de)
DE (1) DE3879722T2 (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0368617A2 (de) * 1988-11-08 1990-05-16 Canon Kabushiki Kaisha Bilderzeugungsgerät mit Kontrollmitteln für die elektrostatische Anziehung von Übertragungsmaterial
EP0400555A2 (de) * 1989-05-30 1990-12-05 Canon Kabushiki Kaisha Bilderzeugungsgerät
EP0500134A2 (de) * 1991-02-22 1992-08-26 Canon Kabushiki Kaisha Bilderzeugendes Gerät
EP0526238A2 (de) * 1991-08-01 1993-02-03 Canon Kabushiki Kaisha Elektrophotographisches Farbgerät
US5276483A (en) * 1988-11-08 1994-01-04 Canon Kabushiki Kaisha Image forming apparatus provided with an attraction charger controlled by one or more ambient conditions
US5313233A (en) * 1989-05-30 1994-05-17 Canon Kabushiki Kaisha Image forming apparatus

Families Citing this family (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5034772A (en) * 1987-09-25 1991-07-23 Canon Kabushiki Kaisha Humidity measurement device and image forming apparatus having the same
JP2631305B2 (ja) * 1988-06-21 1997-07-16 キヤノン株式会社 画像形成装置
US5859948A (en) * 1988-12-06 1999-01-12 Canon Kabushiki Kaisha Images processing apparatus for controlling binarized multi-value image data to convert pulse widths differently in at least two modes
JPH02201365A (ja) * 1989-01-30 1990-08-09 Brother Ind Ltd 画像形成装置
US5029314A (en) * 1989-06-07 1991-07-02 Canon Kabushiki Kaisha Image formation condition controlling apparatus based on fuzzy inference
JP2890487B2 (ja) * 1989-06-23 1999-05-17 ミノルタ株式会社 画像制御装置
JP2769574B2 (ja) * 1989-08-02 1998-06-25 石原産業株式会社 電子写真画像形成方法
US5313308A (en) * 1989-08-31 1994-05-17 Canon Kabushiki Kaisha Image forming apparatus which changes its tone reproducing property in accordance with ambient conditions
JP2898661B2 (ja) * 1989-08-31 1999-06-02 キヤノン株式会社 画像形成装置
JPH0387859A (ja) * 1989-08-31 1991-04-12 Canon Inc 画像形成装置
EP0443535A3 (en) * 1990-02-21 1992-10-28 Tokyo Electric Co., Ltd. Electrophotographic printing apparatus
JP3018395B2 (ja) * 1990-05-15 2000-03-13 ミノルタ株式会社 画像形成装置のトナー濃度制御装置
JPH0434563A (ja) * 1990-05-31 1992-02-05 Toshiba Corp 画像形成装置
JP3010687B2 (ja) * 1990-06-04 2000-02-21 ミノルタ株式会社 画像形成装置
JPH0463367A (ja) * 1990-07-03 1992-02-28 Toshiba Corp 画像形成装置
US5513012A (en) * 1990-07-26 1996-04-30 Canon Kabushiki Kaisha Image forming apparatus having density correction for image formation
US5081498A (en) * 1991-01-10 1992-01-14 Xerox Corporation Humidity compensation in electrophotographic printing by measuring the dielectric characteristics of the development mixture
DE69221947T2 (de) * 1991-06-14 1998-03-05 Canon Kk Bilderzeugungsgerät
US5539500A (en) * 1992-08-31 1996-07-23 Minolta Camera Kabushiki Kaisha Image forming apparatus with humidity controlling device
JP3164961B2 (ja) * 1994-03-18 2001-05-14 株式会社日立製作所 画像記録装置と画質制御方法
JPH09281772A (ja) * 1996-02-16 1997-10-31 Fuji Xerox Co Ltd 画像形成装置
US5701550A (en) * 1996-03-22 1997-12-23 Eastman Kodak Company Method and apparatus for controlling charge on toner in a toning station
WO1998018059A1 (de) * 1996-10-22 1998-04-30 Oce Printing Systems Gmbh Entwicklerstation mit temperatursensor
US6227643B1 (en) 1997-05-20 2001-05-08 Encad, Inc. Intelligent printer components and printing system
JP3981792B2 (ja) * 1999-11-08 2007-09-26 富士フイルム株式会社 画像出力システム
US6866359B2 (en) 2001-01-09 2005-03-15 Eastman Kodak Company Ink jet printhead quality management system and method
US6684036B2 (en) * 2001-03-09 2004-01-27 Hitachi Koki Co., Ltd. Image forming apparatus
US20060117771A1 (en) * 2004-11-10 2006-06-08 Akira Fujimori Image forming apparatus and air intake and exhaust system
US7617017B2 (en) * 2005-02-18 2009-11-10 Gm Global Technology Operations, Inc. System and method for resource reallocation based on ambient condition data
JP4901294B2 (ja) * 2006-04-28 2012-03-21 京セラミタ株式会社 画像形成装置、及び画像形成方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4618246A (en) * 1980-07-22 1986-10-21 Canon Kabushiki Kaisha Image forming device
US4624548A (en) * 1983-07-22 1986-11-25 Canon Kabushiki Kaisha Image density control device
US4627712A (en) * 1983-08-06 1986-12-09 Canon Kabushiki Kaisha Image density control apparatus

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3149668A1 (de) * 1980-12-16 1982-07-15 Canon K.K., Tokyo "farbkopiergeraet"
JPS57178253A (en) * 1981-04-27 1982-11-02 Ricoh Co Ltd Color balancing method in color copying machine
US4502777A (en) * 1981-05-02 1985-03-05 Minolta Camera Kabushiki Kaisha Transfer type electrophotographic copying apparatus with substantially constant potential control of photosensitive member surface
JPS58127948A (ja) * 1982-01-26 1983-07-30 Konishiroku Photo Ind Co Ltd 静電記録装置
JPS58154855A (ja) * 1982-03-10 1983-09-14 Ricoh Co Ltd 複写装置におけるカラ−バランス調整装置
JPS58184137A (ja) * 1982-04-21 1983-10-27 Olympus Optical Co Ltd カメラ
JPS58217960A (ja) * 1982-06-11 1983-12-19 Canon Inc 画像形成装置
JPH0659083B2 (ja) * 1984-12-27 1994-08-03 コニカ株式会社 多色像形成装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4618246A (en) * 1980-07-22 1986-10-21 Canon Kabushiki Kaisha Image forming device
US4624548A (en) * 1983-07-22 1986-11-25 Canon Kabushiki Kaisha Image density control device
US4627712A (en) * 1983-08-06 1986-12-09 Canon Kabushiki Kaisha Image density control apparatus

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, Unexamined Applications, Section E, Vol. 6, No. 77, May 14, 1982 The Patent Office Japanese Government page 3 E 106 & JP-A-57 013 855 (Canon K.K.) *

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0368617A2 (de) * 1988-11-08 1990-05-16 Canon Kabushiki Kaisha Bilderzeugungsgerät mit Kontrollmitteln für die elektrostatische Anziehung von Übertragungsmaterial
EP0368617A3 (en) * 1988-11-08 1990-11-28 Canon Kabushiki Kaisha Image forming apparatus having electrostatic attraction control means for transfer material
US5276483A (en) * 1988-11-08 1994-01-04 Canon Kabushiki Kaisha Image forming apparatus provided with an attraction charger controlled by one or more ambient conditions
EP0400555A2 (de) * 1989-05-30 1990-12-05 Canon Kabushiki Kaisha Bilderzeugungsgerät
EP0400555A3 (de) * 1989-05-30 1992-02-05 Canon Kabushiki Kaisha Bilderzeugungsgerät
US5313233A (en) * 1989-05-30 1994-05-17 Canon Kabushiki Kaisha Image forming apparatus
EP0500134A2 (de) * 1991-02-22 1992-08-26 Canon Kabushiki Kaisha Bilderzeugendes Gerät
EP0500134A3 (en) * 1991-02-22 1992-12-30 Canon Kabushiki Kaisha Image forming apparatus
US5752126A (en) * 1991-02-22 1998-05-12 Canon Kabushiki Kaisha Image forming apparatus
EP0526238A2 (de) * 1991-08-01 1993-02-03 Canon Kabushiki Kaisha Elektrophotographisches Farbgerät
EP0526238A3 (en) * 1991-08-01 1993-08-11 Canon Kabushiki Kaisha A color electrophotographic apparatus

Also Published As

Publication number Publication date
EP0276112B1 (de) 1993-03-31
DE3879722D1 (de) 1993-05-06
DE3879722T2 (de) 1993-10-07
US4888618A (en) 1989-12-19

Similar Documents

Publication Publication Date Title
EP0276112B1 (de) Bilderzeugungseinrichtung
EP0298506B1 (de) Bilderzeugungsgerät
US5682572A (en) Image density control method for an image recorder
US5699096A (en) Potential estimating apparatus using a plurality of neural networks for carrying out an electrophotographic process
US5708917A (en) Toner replenishment device for an image forming apparatus which employs pixel density and toner density information
US5970276A (en) Image forming apparatus and developer aging method
JPH1063048A (ja) 画像形成装置
US4860048A (en) Image forming apparatus
JP2000147861A (ja) 画像形成装置
JP3715758B2 (ja) 画像形成装置
US5539500A (en) Image forming apparatus with humidity controlling device
US5225872A (en) Image forming apparatus having device for determining moisture absorption
US6850718B2 (en) Image forming apparatus for adjusting predetermined developer density values based on a target value and sensed patch developer density
JP2808108B2 (ja) 画像形成装置
US5485191A (en) Image forming apparatus having tone correcting function
JP2604144B2 (ja) 画像形成装置
US6505012B2 (en) Image forming apparatus
JP3188228B2 (ja) 画像濃度補正装置
JPH11219072A (ja) 画像形成装置
JP2641050B2 (ja) 画像形成装置
JPH01205179A (ja) 画像形成装置
JPH04149464A (ja) 画像形成装置
JP3119276B2 (ja) 画像形成装置
JP3227345B2 (ja) 画像形成装置
JPH0973221A (ja) 画像形成装置における電位制御方法及びトナー補給制御方法

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB IT NL

17P Request for examination filed

Effective date: 19881219

17Q First examination report despatched

Effective date: 19910402

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB IT NL

REF Corresponds to:

Ref document number: 3879722

Country of ref document: DE

Date of ref document: 19930506

ET Fr: translation filed
ITF It: translation for a ep patent filed

Owner name: SOCIETA' ITALIANA BREVETTI S.P.A.

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
ITTA It: last paid annual fee
REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 20070115

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20070117

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20070321

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20070611

Year of fee payment: 20

REG Reference to a national code

Ref country code: GB

Ref legal event code: PE20

NLV7 Nl: ceased due to reaching the maximum lifetime of a patent

Effective date: 20080118

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20080118

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20070123

Year of fee payment: 20

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20080117